package pay;

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;


public class RSA {
    private static final String SIGN_ALGORITHMS = "SHA1WithRSA";

    private static final String SIGN_ALGORITHMSRSA2 = "SHA256WithRSA";

    /**
     * RSA验签名检查
     *
     * @param content       待签名数据
     * @param sign          签名值
     * @param
     * @param input_charset 编码格式
     * @return 布尔值
     */
    public static boolean verify(String content, String sign, String pub_key, String input_charset) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(pub_key);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));


            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);

            signature.initVerify(pubKey);
            signature.update(content.getBytes(input_charset));

            return signature.verify(Base64.decode(sign));

        } catch (Exception e) {
            e.printStackTrace();
        }

        return false;
    }

    /**
     * RSA签名
     *
     * @param content       待签名数据
     * @param privateKey    商户私钥
     * @param input_charset 编码格式
     * @return 签名值
     */
    public static String sign(String content, String privateKey, String input_charset) {
        try {
            PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64.decode(privateKey));
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyf.generatePrivate(priPKCS8);

            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);

            signature.initSign(priKey);
            signature.update(content.getBytes(input_charset));

            byte[] signed = signature.sign();

            return Base64.encode(signed);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * RSA2签名
     *
     * @param content       待签名数据
     * @param privateKey    商户私钥
     * @param input_charset 编码格式
     * @return 签名值
     */
    public static String signRsa2(String content, String privateKey, String input_charset) {
        try {
            PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64.decode(privateKey));
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyf.generatePrivate(priPKCS8);
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMSRSA2);
            signature.initSign(priKey);
            signature.update(content.getBytes(input_charset));

            byte[] signed = signature.sign();

            return Base64.encode(signed);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * RSA2验签名检查
     *
     * @param content       待签名数据
     * @param sign          签名值
     * @param
     * @param input_charset 编码格式
     * @return 布尔值
     */
    public static boolean verifyRsa2(String content, String sign, String pub_key, String input_charset) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(pub_key);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMSRSA2);
            signature.initVerify(pubKey);
            signature.update(content.getBytes(input_charset));

            return signature.verify(Base64.decode(sign));

        } catch (Exception e) {
            e.printStackTrace();
        }

        return false;
    }

}
